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/*-
* Copyright (c) 2012 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Pawel Jakub Dawidek under sponsorship from
* the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/capsicum.h>
#include <sys/procdesc.h>
#include <sys/socket.h>
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <paths.h>
#include <stdbool.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <libcapsicum.h>
#include <libcapsicum_impl.h>
#include <nv.h>
#include <pjdlog.h>
#include "zygote.h"
/* Zygote info. */
static int zygote_sock = -1;
static void
stdnull(void)
{
int fd;
fd = open(_PATH_DEVNULL, O_RDWR);
if (fd == -1)
errx(1, "Unable to open %s", _PATH_DEVNULL);
if (setsid() == -1)
errx(1, "Unable to detach from session");
if (dup2(fd, STDIN_FILENO) == -1)
errx(1, "Unable to cover stdin");
if (dup2(fd, STDOUT_FILENO) == -1)
errx(1, "Unable to cover stdout");
if (dup2(fd, STDERR_FILENO) == -1)
errx(1, "Unable to cover stderr");
close(fd);
}
int
zygote_clone(zygote_func_t *func, int flags, int *chanfdp, int *procfdp)
{
nvlist_t *nvl;
int error;
if (zygote_sock == -1) {
/* Zygote didn't start. */
errno = ENXIO;
return (-1);
}
nvl = nvlist_create(0);
nvlist_add_number(nvl, "func", (uint64_t)(uintptr_t)func);
nvlist_add_number(nvl, "flags", (uint64_t)flags);
nvl = nvlist_xfer(zygote_sock, nvl);
if (nvl == NULL)
return (-1);
if (nvlist_exists_number(nvl, "error")) {
error = (int)nvlist_get_number(nvl, "error");
nvlist_destroy(nvl);
errno = error;
return (-1);
}
*chanfdp = nvlist_take_descriptor(nvl, "chanfd");
*procfdp = nvlist_take_descriptor(nvl, "procfd");
nvlist_destroy(nvl);
return (0);
}
/*
* This function creates sandboxes on-demand whoever has access to it via
* 'sock' socket. Function sends two descriptors to the caller: process
* descriptor of the sandbox and socket pair descriptor for communication
* between sandbox and its owner.
*/
static void
zygote_main(int sock)
{
int error, fd, flags, procfd;
int chanfd[2];
nvlist_t *nvlin, *nvlout;
zygote_func_t *func;
pid_t pid;
assert(sock > STDERR_FILENO);
setproctitle("zygote");
if (pjdlog_mode_get() != PJDLOG_MODE_STD)
stdnull();
for (fd = STDERR_FILENO + 1; fd < sock; fd++)
close(fd);
closefrom(sock + 1);
for (;;) {
nvlin = nvlist_recv(sock);
if (nvlin == NULL) {
if (errno == ENOTCONN) {
/* Casperd exited. */
exit(0);
}
continue;
}
func = (zygote_func_t *)(uintptr_t)nvlist_get_number(nvlin,
"func");
flags = (int)nvlist_get_number(nvlin, "flags");
nvlist_destroy(nvlin);
/*
* Someone is requesting a new process, create one.
*/
procfd = -1;
chanfd[0] = -1;
chanfd[1] = -1;
error = 0;
if (socketpair(PF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0,
chanfd) == -1) {
error = errno;
goto send;
}
pid = pdfork(&procfd, 0);
switch (pid) {
case -1:
/* Failure. */
error = errno;
break;
case 0:
/* Child. */
close(sock);
close(chanfd[0]);
func(chanfd[1]);
/* NOTREACHED */
exit(1);
default:
/* Parent. */
close(chanfd[1]);
break;
}
send:
nvlout = nvlist_create(0);
if (error != 0) {
nvlist_add_number(nvlout, "error", (uint64_t)error);
if (chanfd[0] >= 0)
close(chanfd[0]);
if (procfd >= 0)
close(procfd);
} else {
nvlist_move_descriptor(nvlout, "chanfd", chanfd[0]);
nvlist_move_descriptor(nvlout, "procfd", procfd);
}
(void)nvlist_send(sock, nvlout);
nvlist_destroy(nvlout);
}
/* NOTREACHED */
}
int
zygote_init(void)
{
int serrno, sp[2];
pid_t pid;
if (socketpair(PF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0, sp) == -1)
return (-1);
pid = fork();
switch (pid) {
case -1:
/* Failure. */
serrno = errno;
close(sp[0]);
close(sp[1]);
errno = serrno;
return (-1);
case 0:
/* Child. */
close(sp[0]);
zygote_main(sp[1]);
/* NOTREACHED */
abort();
default:
/* Parent. */
zygote_sock = sp[0];
close(sp[1]);
return (0);
}
/* NOTREACHED */
}
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